NASA eyes shuttle's future
Falling foam vexes engineers
By Thom Patterson
Crew members stand in front of the shuttle after landing.
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(CNN) -- With Discovery and its crew safely back on Earth, NASA turned its attention Tuesday to the next space shuttle mission and a threat to the orbiter that has put future flights on hold.
The "only thing that went wrong" during Discovery's mission, NASA Administrator Mike Griffin said, was falling insulating foam during its launch. Griffin has ordered that no shuttle mission will fly until engineers determine how to fix the problem.
Shuttle Atlantis had been scheduled to lift off during a launch window in September, but officials acknowledge that is now unlikely.
But pressure is on NASA to meet its obligations to finish construction on the orbiting international space station.
"We're going to try as hard as we can to get back in space this year, because we have a big construction project we're working on and we need the shuttle to do it," Griffin said at a Florida news conference Tuesday. "So we're going to try as hard as we can, but we're not going to go until we're ready to go."
NASA engineers have been working on the foam problem after shedding was videotaped during Discovery's July 26 launch.
None of the debris appeared to damage the orbiter.
The insulating foam prevents ice from forming on the shuttle's exterior fuel tank, which gets very cold from its contents of low-temperature liquid hydrogen and oxygen.
Shedding -- which was blamed for the Columbia disaster in 2003 -- was supposed to have been resolved for Discovery's mission.
Columbia investigators determined that foam struck the shuttle during launch, dooming the orbiter to break apart when it re-entered Earth's atmosphere.
In the wake of the tragedy, NASA spent millions of dollars to redesign the liquid fuel tank.
NASA said it would never be able to eliminate shedding completely, but engineers thought they had eliminated the shedding of large pieces of debris.
They had hoped that any debris shed would be no heavier than three-hundredths of a pound.
A piece that broke loose from Discovery is thought to have weighed nine-tenths of a pound.
The piece of foam that doomed Columbia weighed 1.6 pounds.
Discovery has brought back new data that engineers may be able to use to minimize foam shedding from future fuel tanks.
"We always knew this was a test flight that was going to give us a lot of information," said Bill Parsons, shuttle program manager. "We have some things that we learned and that we have to go to work on."
Griffin has said that the shuttle program will end in 2010, to make way for a new vehicle -- dubbed the Crew Exploration Vehicle (CEV), designed to take astronauts back to the moon and perhaps beyond to Mars.
'A great achievement'
Discovery landed Tuesday at Edwards Air Force base in California, after bad weather in Florida prompted NASA to redirect it there. (Full story)
From his ranch in Crawford, Texas, President Bush congratulated shuttle commander Eileen Collins and the entire crew for a successful mission.
"It was a great achievement. It was important for NASA as it regains the confidence of the American people and begins to transition to the new mission we've set out for NASA," the president said.
A CNN/USA Today/Gallup Poll conducted Friday through Saturday shows Americans are confident NASA can make the space shuttle safe to fly future missions, with 41 percent saying they were very confident and 42 percent responding that they were somewhat confident.
Thirteen percent of the 1,004 adults questioned said they were not too confident that NASA could make the shuttle safe enough to fly again.
When asked to rate the job being done by NASA, 16 percent said it was excellent and 44 percent said it was good.
The excellent rating was up from 12 percent when the same question was posed seven months after Columbia disintegrated upon re-entering the Earth's atmosphere in February 2003.
In the latest sampling, 29 percent of those asked felt NASA was only doing a fair job, and 8 percent said it was doing a poor job.
The sampling error is plus or minus 3 percentage points.
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